The present invention relates generally to the field of integrated circuit design, and more particularly to accommodating engineering change orders by including spare latch circuits.
Integrated circuit design is a complex and drawn-out process. From time to time, requirements to change a circuit design are made after substantial design work has been completed. These requests, termed “Engineering Change Orders” (“ECOs”) introduce additional complexity into the process. Engineers anticipate ECOs by including extra combinatorial logic and spare latches, which can be reconfigured, if needed, by metal-only ECO. Metal-only ECO is common practice in Complementary Metal-Oxide Semiconductor (CMOS) designs. In metal-only ECO, only a few of the masks for the original design are altered, typically for metal layers, hence the designation metal-only. Using metal-only ECO, engineers can activate extra latches, gates, and other structures that have been placed in the design in case of an eventual ECO requirement for additional structures. Engineers continue to face challenges in anticipating and facilitating ECOs.